Companies have the opportunity to reduce the complexity of their IT infrastructure and their IT costs by using virtualization technologies and cloud computing services. In general, virtualization refers to the simultaneous hosting of one or more operating systems on a physical computer. Such virtual operating systems and their associated virtual resources are called virtual machines. Virtualization software (or synonymously, a hypervisor or Virtual Machine Monitor), sits between the virtual machines and the hardware of the physical computer, which is called a virtual machine host. One example of virtualization software is ESX Server, by VMware, Inc. of Palo Alto, Calif. Other examples include Microsoft Virtual Server and Microsoft Windows Server Hyper-V, both by Microsoft Corporation of Redmond, Wash., and Sun xVM by Oracle America Inc. of Santa Clara, Calif.
Virtualization software provides to each virtual operating system virtual resources, such as virtual processors, virtual memory, virtual network devices, and virtual disks. Each virtual machine has one or more virtual disks to store the files, metadata, and other data used by the virtual machine. Virtualization software typically stores the data of virtual disks in files on the file system of the physical computer, called virtual machine disk files (in the case of VMware virtual servers) or virtual hard disk image files (in the case of Microsoft virtual servers). For example, VMware's ESX Server provides the Virtual Machine File System (VMFS) for managing virtual machine disk files. A virtual machine reads data from and writes data to its virtual disk much the same way that an actual physical machine reads data from and writes data to an actual disk.
Cloud computing services (or “cloud services”) provide computing as a service by sharing resources and software to computing devices over a network such as the Internet, typically as a paid (e.g., metered or subscription) service. For example, cloud services provide storage resources, computational power, software, and data access to their customers, who are generally unaware of the underlying structure of the physical devices and software that facilitate the services. Examples of cloud computing service vendors include Amazon Corporation of Seattle, Wash. (offering Amazon Web Services); Rackspace Corporation of San Antonio, Tex.; and Microsoft Corporation of Redmond, Wash. (offering Windows Azure).
A cloud service often provides an Application Programming Interface (“API”) or similar interface that enables a cloud service customer's machines to access, modify, and otherwise manage the customer's cloud services and data. Typically, cloud services are facilitated by virtualization. For example, in order to provide data storage, access, and computational resources for customers, a cloud service provider may operate a data center having multiple virtual machine hosts, each of which runs multiple virtual machines.
When companies transition their existing in-house physical IT infrastructure, such as existing application servers, to virtual machines and cloud services, they may experience numerous difficulties. For example, the company's IT staff may be unfamiliar with virtualization software or cloud service APIs and therefore spend substantial internal resources familiarizing themselves with these. Alternatively, a company's IT staff may be familiar with using only a single virtualization or cloud computing service vendor and therefore miss the opportunity to transition to a different, more cost-effective vendor. The internal IT staff may also incorrectly transition existing application servers or stored data to a new virtualized or cloud platform. Moreover, even if IT staff are familiar with numerous virtualization and cloud service vendors, they may need to spend substantial time and energy cataloguing existing physical IT resources, designing and deploying comparable virtualization or cloud services platforms to replace those physical resources, porting existing applications to the new platforms, testing the new platforms, and redirecting client service requests to the new platforms.
Some systems and software may convert a physical machine to a virtual machine. However, typically such systems and software require that all of the production data of the physical machine be read and transmitted over a network, which requires substantial time and network bandwidth. These systems and software also typically require that the same data be stored twice: once at the source physical machine and once at the destination virtual machine. Moreover, such systems and software typically must perform substantial processing to convert the production data of the physical machine to a virtual disk file (e.g., a .vmdk file). Further, such systems and software typically cannot create a virtual machine from an earlier, point-in-time state of the physical machine, but can only create a virtual machine reflecting the state of the physical machine at the present time when the virtual machine is being created.
The need exists for systems and methods that overcome the above problems, as well as systems and methods that provide additional benefits. Overall, the examples herein of some prior or related systems and methods and their associated limitations are intended to be illustrative and not exclusive. Other limitations of existing or prior systems and methods will become apparent to those of skill in the art upon reading the following Detailed Description.